How to Grow Yacon
Smallanthus sonchifolius
Yacon is a South American tuber crop producing sweet, crunchy roots with a flavour between apple and watermelon. Grow from rhizome divisions started indoors in March. Plant out after last frost into rich, moisture-retentive soil in full sun. Plants grow tall (1.5-2 m) and bushy, resembling sunflowers. Harvest after first frost blackens foliage — dig carefully as tubers snap easily. Leave harvested tubers in sunlight for 1-2 weeks to sweeten. Save small crown rhizomes for next year.
When to Start
Sow indoors 6 weeks before last frost, or direct sow outdoors after frost risk has passed and soil reaches 12°C.
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Growth Stages
Approximate days from start
Care Essentials
- Apply a balanced general-purpose feed monthly from June to August. Avoid high-nitrogen feeds which promote foliage at the expense of tuber development.
- Yacon is grown from rhizome offsets (crown divisions), not seed. Start indoors in pots from March, plant out after last frost in May. Plants grow tall (1.5-2 m) and may need staking in exposed sites. Save a few small rhizomes each year for replanting.
Growing Conditions
- Min. soil temperature
- 12°C+
- Germination temperature
- 15–25°C
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- Sow indoors
- —
- Transplant out
- —
- First harvest
- —
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Spacing & Planting
| Plant spacing | 75 cm |
| Row spacing | 90 cm |
| Sow depth | 5 cm |
| Mature height | 200 cm |
| Mature spread | 80 cm |
Space 60-90 cm apart. Plants grow tall (up to 2 m) and bushy by late summer, so allow room for air circulation. A catch crop of salads can be grown between plants early in the season.
Pests & Diseases
Pest Slugs and Snails
Identification: Irregular holes in young leaves, slime trails visible on soil and foliage, damage worst in wet weather
- Beer traps
- Copper tape around pots
- Evening patrols
- Nematode biological control (Nemaslug)
- Ferric phosphate pellets
Disease Crown Rot
Symptoms: Soft, mushy crown tissue during storage, foul smell, spreads to stored rhizomes
Treatment: Discard affected material, ensure good air circulation during curing, store in barely-damp compost
Prevention: Cure tubers in dry conditions before storage, avoid damage during harvest, store in cool frost-free conditions
Growing Conditions
| Min. soil temperature | 12°C |
| Germination temperature | 15–25°C |
| Base growth temperature | 10°C |
| Min. daylength to start | 12h |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Yacon?
- Plant Yacon 75cm apart with 90cm between rows.
- When can I harvest Yacon?
- Yacon is ready to harvest approximately 150 days after transplanting.
- Is Yacon frost hardy?
- Yacon is classified as Half Hardy.
